Trocar cannula assembly and method of manufacture

ABSTRACT

A cannula assembly having a retention member and a method of manufacture of the cannula assembly is provided. The cannula assembly includes a cannula and a sleeve disposed around the cannula from a proximal end to a distal end. The sleeve can be pre-formed by a stretch blow molding process then advanced over the cannula. The sleeve includes an inflatable balloon and an annular ring distal the inflatable balloon. The cannula includes an annular recess. The annular ring is sized to have an interference fit with the annular recess.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/588,929, entitled “TROCAR CANNULA ASSEMBLY AND METHOD OFMANUFACTURE,” filed on Aug. 17, 2012, currently pending, which claimsthe benefit of U.S. Provisional Patent Application No. 61/528,118,entitled “BALLOON TROCAR WITH FOLDED BALLOON AND METHOD OF MANUFACTURINGTHE SAME,” filed on Aug. 26, 2011, and U.S. Provisional PatentApplication No. 61/528,716, entitled “BALLOON TROCAR WITH FOLDED BALLOONAND METHOD OF MANUFACTURING THE SAME,” filed on Aug. 29, 2011. Theentireties of these applications are hereby incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This application relates generally to surgical access systems andmethods of manufacturing such systems and, more specifically, to balloontrocars with retention components and methods of manufacturing the same.

2. Description of the Related Art

Surgical access systems such as trocar systems facilitate minimallyinvasive surgery across a body wall and within a body cavity. Forexample, in abdominal surgery, trocars provide a working channel acrossthe abdominal wall to facilitate the use of instruments within theabdominal cavity. Trocar systems typically include a cannula, whichprovides the working channel, and an obturator that is used to place thecannula across a body wall, such as the abdominal wall. The obturator isinserted into the working channel of the cannula and pushed through thebody wall with a penetration force of sufficient magnitude to result inpenetration of the body wall. Alternatively, the cannula with anobturator is passed through an incision formed by the “Hasson,” orcut-down, technique, which includes incremental incisions through thebody wall until the body wall is incised through its entire thickness.Once the cannula has traversed the body wall, the obturator can beremoved.

With the cannula in place in the body wall, various instruments may beinserted through the cannula into the body cavity. One or more cannulaemay be used during a procedure. During the procedure, the surgeonmanipulates the instruments in the cannulae, sometimes using more thanone instrument at a time. The manipulation of an instrument by a surgeonmay cause frictional forces between the instrument and the cannula inwhich the instrument is inserted. These frictional forces may result inmovement of the cannula in an inward or outward direction within thebody wall. If the cannula is not fixed in place, the proximal or distalmotions of the instruments through the cannula may potentially cause thecannula to slip out of the body wall or to protrude further into thebody cavity, possibly leading to injury to the patient.

The surfaces of the cannula associated with a trocar are generallysmooth. The smoothness of a cannula surface makes placement of thecannula through a body wall relatively easy and safe. However, a smoothcannula may not have the desired retention characteristics once thecannula has been placed through a body wall. This smoothness and ease ofplacement may present problems as instruments and specimens are removedfrom a body cavity through the cannula and the associated seal systemsof the trocar. It is highly desirable for a cannula to remain fixed inan appropriate position once placed. Additionally, if the Hassontechnique is used, the incision may be larger than the cannula that maybe placed through the incision. Therefore, it is desirable to provide ameans to seal the incision site after the cannula has been inserted inorder to insufflate a patient.

Various solutions to the issue of trocar-cannula fixation orstabilization have been attempted. These attempts include an inflatableballoon attached to the distal portion of the cannula with a thick foambolster proximal to the insertion point into the body wall, raisedthreads or raised rings associated with the outer surface of thecannula, mechanically deployable enlarging portions arranged at thedistal end of a cannula and suture loops or hooks associated with theproximal end of the trocar. These attempts have provided some degree offixation or stabilization, but they have often led to cannulae having arelatively large outside diameter. Further, the thick foam bolsterassociated with balloon trocars has reduced the usable length of thecannula. There remains a need for a cannula fixation or stabilizationdevice that includes a sleeve having retention means that minimize theincrease in diameter. Additionally, the cannula fixation orstabilization device may include a lower profile and increase theworking length of the cannula.

Methods for achieving the above comprise inflatable toroidal balloonsthat are sized larger than the cannula associated with the access deviceand usually disposed at or toward the distal end thereof. Duringinsertion of the access channel through a body wall, the balloon isdeflated. The balloon is inflated when the access channel is within thebody cavity and properly placed. Most of the balloons associated withaccess devices are distensible or made of an elastic material. In somecases the balloons are made of a non-distensible or non-elasticmaterial.

SUMMARY OF THE INVENTION

A balloon trocar, in various embodiments in accordance with the presentinvention, can be used in general, abdominal, gynecological and thoracicminimally invasive surgical procedures to establish a path of entry orto gain access through the tissue planes and/or potential spaces forendoscopic instruments. In various embodiments, a balloon trocarcomprises an inflatable balloon at the distal end of a trocar cannulaand a bolster toward the proximal end of the cannula. To use the balloontrocar, a surgeon inserts the balloon trocar into the body cavity suchthat the balloon section of the cannula is within the cavity, e.g., forabdominal surgery, beyond the peritoneal lining and within the abdominalcavity. The balloon is inflated and the bolster located toward theproximal end of the cannula is moved distally along the length of thecannula in order to compress the balloon against the inside of the bodywall and seal the incision. With the bolster against the outer surfaceof the body wall, the balloon is maintained in compression against theinner surface of the body wall. In this manner, a seal is createdbetween the balloon and the body wall, thereby allowing a surgeon toinsufflate a patient. The balloon may remain inflated during theduration of a laparoscopic surgery, which may last up to four hours ormore.

An elastic balloon is formed as a small inflatable structure. Whendeflated, an elastic balloon assumes a natural “low-profile” conditionand conforms to the outer surface of the access channel or cannula. Anon-elastic balloon is formed to assume a preferred maximum size andshape in a natural condition. Therefore, there exists a surplus ofnon-elastic balloon material when the balloon is deflated. As such,non-elastic balloon structures associated with an access channel thatclosely conforms to the exterior of the access channel and minimizes theinterference between the deflated balloon and the tissue of a body wallduring the insertion of the access device are desirable.

In accordance with various embodiments of the present invention, aballoon trocar is provided in which the balloon or retention componentreduces insertion force of the balloon trocar. In one embodiment, aballoon or expandable membrane positioned on or near the distal end ofthe cannula of the trocar is void or without or having little air withinthe balloon and is folded proximally or away from the direction in whichthe trocar is to be inserted into the body cavity. The evacuation of airand folding of the balloon reduces resistance and the insertion forceused to insert the cannula within the body cavity without reducingballoon strength to maintain retention by the balloon and integrity ofthe seal and the balloon itself. Additionally, such a balloon permitsthe utilization of a reduced insertion force relative to the insertionforce of a non-folded balloon. A reduced insertion force permits a morecontrolled entry of the trocar into the body cavity. A more controlledentry reduces inadvertent and undesirable contact with organs, tissue,other inserted devices or ports within the body cavity. Also, a reducedinsertion force reduces potential trauma to the incision or entry siteas less force is applied to the site as the trocar is being insertedinto the body cavity.

In various embodiments, an access channel or cannula that is associatedwith a surgical access device or trocar is provided. The cannula issized and configured to receive a retention and stabilizing balloonalong the distal portion. A non-elastic balloon made of polyolefin,nylon, polyester, polyethylene or the like is placed along a locationupon the cannula. The deflated non-elastic balloon is maintained in thelowest profile condition for insertion through a body wall. The balloonconforms very closely the profile of the cannula. A folded ballooncondition is maintained.

In certain embodiments, a cannula assembly is provided. The cannulaassembly comprises a cannula and a sleeve. The cannula has a proximalend, a distal end opposite the proximal end, and a lumen extending fromthe proximal end to the distal end along a longitudinal axis. The lumenis configured to receive a surgical instrument therein. The cannulacomprises a generally tubular cannula body and an annular recess. Thegenerally tubular cannula body has an exterior surface and a first outerdiameter. The annular recess is formed in the exterior surface of thecannula body adjacent the distal end of the cannula. The annular recessis transverse to the longitudinal axis. The annular recess has a secondouter diameter smaller than the first outer diameter of the cannulabody. The sleeve has a proximal end and a distal end. The sleeve isdisposed around the cannula from adjacent the proximal end of thecannula to the annular recess. The sleeve comprises an elongate tubularbody, a balloon positioned distal the elongate tubular body, and anannular ring distal the balloon. The annular ring is positioned in theannular recess of the cannula. The annular ring has a third innerdiameter in an undisturbed state. The third inner diameter of theannular ring is smaller than the second outer diameter of the annularrecess to define an interference fit between the sleeve and the cannula.

In certain embodiments, a cannula assembly is provided. The cannulaassembly comprises a cannula and a sleeve. The cannula has a proximalend, a distal end opposite the proximal end, and a lumen extending fromthe proximal end to the distal end along a longitudinal axis. The lumenis configured to receive a surgical instrument therein. The cannulacomprises a fluid inlet port adjacent the proximal end, a generallytubular cannula body extending from fluid inlet port to the distal endof the cannula, an annular groove formed in the exterior surface of thecannula body adjacent the distal end of the cannula, and a distal tip atthe distal end of the cannula body. The fluid inlet port comprises afluid inlet to receive a source of inflation fluid and a fluid domefluidly coupled to the fluid inlet. The fluid dome has a generallysmooth outer surface. The cannula body has an exterior surface and afirst outer diameter. The annular groove is transverse to thelongitudinal axis. The annular groove has a proximal edge, a distaledge, and an annular surface between the proximal edge and the distaledge. The annular surface has a second outer diameter smaller than thefirst outer diameter of the cannula body. The distal tip has a distaledge extending at a transverse angle relative to a plane perpendicularthe longitudinal axis. The sleeve has a proximal end and a distal end.The sleeve is disposed around the cannula from the fluid inlet port tothe annular groove. The sleeve comprises a balloon positioned adjacentthe distal end of the sleeve, and an annular ring distal the balloon.The annular ring is positioned in the annular groove.

In certain embodiments, a cannula assembly is provided. The cannulaassembly comprises a cannula and a sleeve. The cannula has a proximalend, a distal end opposite the proximal end, and a lumen extending fromthe proximal end to the distal end along a longitudinal axis. The lumenis configured to receive a surgical instrument therein. The cannulacomprises a generally tubular cannula body extending from adjacent theproximal end to the distal end of the cannula and an annular grooveformed in the exterior surface of the cannula body adjacent the distalend of the cannula. The cannula body has an exterior surface and a firstouter diameter. The annular groove is transverse to the longitudinalaxis. The annular groove has a second outer diameter smaller than thefirst outer diameter of the cannula body. The sleeve has a proximal endand a distal end. The sleeve is disposed around the cannula fromadjacent the proximal end to the annular groove. The sleeve is formed ina monolithic, unitary construction. The unitary construction comprises acoupler at the proximal end, an elongate tubular body extending distallyfrom the coupler, a balloon positioned distal the elongate tubular body,and an annular ring distal the balloon. The coupler is sized andconfigured to engage the cannula. The elongate tubular body has a firstthickness. The balloon has a second thickness smaller than the firstthickness. The annular ring is positioned in the annular groove of thecannula. The annular ring has a third thickness and a third innerdiameter in an undisturbed state. The third thickness is larger than thefirst thickness of the elongate tubular body. The third inner diameterof the annular ring in an undisturbed state is smaller than the secondouter diameter of the annular groove to define an interference fitbetween the sleeve and the cannula.

In certain embodiments, a method of making a cannula assembly having aninflatable balloon is provided. The method comprises stretch blowmolding a blank to preform a sleeve, advancing the preformed sleeve overa cannula, positioning an annular ring of the sleeve in an annulargroove of the cannula, and bonding the sleeve to the cannula. The sleevehas a proximal end and a distal end. The sleeve comprises an elongatetubular body, a balloon distal the tubular body, and an annular ringdistal the balloon. The cannula has a proximal end and a distal end. Thecannula comprises an elongate cannula body with an annular groove formedin the cannula body at the distal end of the cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of a laparoscopic surgical procedure;

FIG. 2 illustrates a plan view of a laparoscopic surgical procedureshowing the placement of trocars;

FIG. 3 illustrates a perspective view of a prior art assembled trocarand obturator;

FIG. 4 illustrates a perspective view of a prior art assembled trocarwithout an obturator;

FIG. 5 illustrates a perspective view of a prior art cannula;

FIG. 6 illustrates a perspective view of a prior art assembled threadedtrocar and obturator;

FIG. 7 illustrates a perspective view of a prior art threaded cannulaand housing;

FIG. 8 illustrates a perspective view of a prior art threaded cannula;

FIG. 9 illustrates a perspective view of a prior art cannula having anuninflated balloon at the distal end;

FIG. 10 illustrates a perspective view of a prior art cannula having aninflated balloon at the distal end;

FIG. 11 illustrates a prior art trocar-cannula having a distal retentionballoon placed through a body wall in a first position;

FIG. 12 illustrates a prior art trocar-cannula having a distal retentionballoon placed through a body wall in a second position;

FIG. 13 illustrates a perspective view of an embodiment of trocarcannula assembly;

FIG. 14 illustrates a perspective view of an embodiment of sleevesubassembly of the trocar cannula assembly of FIG. 13;

FIG. 15 illustrates a perspective view of an embodiment of cannula ofthe trocar cannula assembly of FIG. 13;

FIG. 16 illustrates a detail cut away view of a distal end of thecannula of FIG. 15;

FIG. 17 illustrates a perspective view of an embodiment of sleeve of thetrocar cannula assembly of FIG. 13 as manufactured by a stretch blowmolding process;

FIG. 18 illustrates a perspective view of the sleeve of FIG. 17 in aninstallation configuration;

FIG. 19 illustrates a partial cross-sectional view of the distal end ofthe trocar cannula assembly of FIG. 13;

FIG. 20 illustrates a detail cut away view of the trocar cannulaassembly of FIG. 13;

FIG. 21 illustrates a perspective view of a retention disk of the trocarcannula assembly of FIG. 13;

FIG. 22 illustrates a cross-sectional view of the retention disk of FIG.21;

FIG. 23 illustrates a perspective view of a sleeve protector of thetrocar cannula assembly of FIG. 13;

FIG. 24 illustrates a partial cross-sectional view of the distal end ofthe trocar cannula assembly of FIG. 13;

FIG. 25 illustrates an embodiment of a method for manufacturing a trocarcannula assembly;

FIG. 26 illustrates another embodiment of a method for manufacturing atrocar cannula assembly;

FIG. 27 illustrates another embodiment of a method for manufacturing atrocar cannula assembly;

FIG. 28 illustrates another embodiment of a method for manufacturing atrocar cannula assembly;

FIG. 29 illustrates another embodiment of a method for manufacturing atrocar cannula assembly;

FIG. 30 illustrates a partial cross-sectional view of an embodiment oftrocar cannula assembly in a partially-assembled configuration;

FIG. 31 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration;

FIG. 32 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with aballoon in a deflated state;

FIG. 33 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with aballoon in a deflated state;

FIG. 34 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with aballoon in a deflated state and a sleeve protector advanced over theballoon;

FIG. 35 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configurationundergoing a sterilization process;

FIG. 36 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with aballoon in a folded insertion configuration;

FIG. 37 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with apre-creased balloon;

FIG. 38 illustrates an exemplary graph of an insertion force in poundsversus elapsed time for a trocar cannula having a non-folded balloon;and

FIG. 39 illustrates an exemplary graph of an insertion force in poundsversus elapsed time for a trocar cannula having a proximally-foldedballoon.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 2, a typical laparoscopic procedure isillustrated where a plurality of trocars 100 are placed through a bodywall 50, such as an abdominal wall, and into a body cavity 52, such asan abdominal cavity. The body cavity 52 is insufflated, or inflated withgas, to distend the body wall 50 and provide a working space for thelaparoscopic procedure. The trocars 100 each include a cannula 110 and aseal 150. Positive pressure is maintained within the body cavity 52 bythe seal 150 associated with the cannula 110. In addition, the cannula110 must form a gas-tight seal against adjacent tissue. If positivepressure is lost, either through the seal 150 associated with thecannula 110 or the seal between the cannula and the adjacent tissue, theprocedure may be compromised.

As the body cavity 52 is inflated, the body wall 50 may be greatlydistended. The access sites may tend to enlarge under the distention ofthe body wall 50 and compromise the positioning and sealing of thecannula 110. As stated above, the manipulation of instruments 190 usedthrough the trocars 100 may result in movement of the cannulae 110 ineither a proximal or distal direction within the access site through thebody wall 50. As this occurs, some liquefaction may take place and thepreferred relationship between the cannula 110 and the body tissue maybe compromised.

Referring now to FIGS. 3-6, a typical assembled trocar 100 is shownhaving a cannula 110, a seal housing 150 and an obturator 160. Thecannula 110 typically has a smooth exterior surface 102 so that it maybe inserted through the body wall 50 easily. The seal housing 150contains a seal system that prevents retrograde gas-flow. The obturator160 is a cutting or piercing instrument that creates the pathway throughthe body wall 50 through which the cannula 110 follows. Surgicalobturators 160 are generally sized and configured to create a defect intissue that is appropriate for the associated cannula 110. However, thedefect may have a tendency to enlarge during a surgical procedure as thetrocar 100 or cannula 110 is manipulated. As an instrument 190 is urgeddistally and proximally, or inserted and withdrawn, the cannula 110 maymove or even be inadvertently withdrawn due to the friction between theinstrument 190 and the seal 150 of the trocar housing.

With specific reference to FIGS. 6-8, a trocar 100 or access device isshown where the outer surface 102 of the cannula 110 includes aplurality of raised features 115. These raised features 115 are sizedand configured to increase resistance to proximal and distal motion asinstruments 190 are maneuvered, and especially as specimens are removed,through the trocar 100. The prior art includes either sequential raisedrings or a raised coarse-thread 115. While the rings or threads 115 ofthe prior art may stabilize the cannula 110 to some degree, they do notnecessarily seal the cannula 110 against the adjacent tissue of a bodywall 50. There may be gas loss associated with the use of these systems.The raised rings or threads 115 also increase the insertion forcerequired to penetrate a body wall 50. The insertion force may be reducedin the instance of a continuous coarse thread 115 in comparison to asequence of discrete raised rings or features as a threaded cannula 110may actually be “screwed” into the tissue defect in accordance with thethread direction and pitch, rather than pushed through withoutappropriate rotation.

With reference to FIGS. 9-12, a surgical access device 100 according toprior art includes a cannula 110 having an inflatable balloon 120associated with the distal-end portion 122 of the cannula. The balloon120 is sized and configured to fit snugly around the cannula 110 in theuninflated condition. The balloon 120 is inflated after the cannula 110is properly placed through the body wall 50 and into the body cavity 52.The balloon 120 is generally held against the interior surface 54 of thebody wall 50 by a counter-force that is associated with a slidingcounter-force member, such as a foam bolster 180. The bolster 180 isassociated with the proximal portion of the cannula 110. The balloons120 associated with the devices of the prior art are typically“thick-walled” structures constructed as part of the cannula 110. Theballoon 120 is generally bonded to the distal-end portion 122 of thecannula 110 and an inflation channel or lumen is provided within thewall of the cannula 110.

With reference to FIG. 13, an embodiment of trocar cannula assembly 210having advanced fixation features is illustrated. The trocar cannulaassembly 210 can include a seal housing 212 and a sleeve sub assembly214 comprising a trocar cannula 216, a sleeve 218 including aninflatable balloon 220, a retention disc 222, and a tip protector 224 orsleeve protector.

With continued reference to FIG. 13, the seal housing 212 or valvehousing can include an instrument seal and a zero seal. In someembodiments, the valve housing can be removably coupled to the cannula216 and in one embodiment includes an inlet for supplying insufflationgas into a body cavity such as the abdominal cavity. The instrument sealand zero seal enclosed in the valve housing in various embodiments canbe separate or monolithic seals. The zero seal and instrument seal canseal an instrument path through the valve housing into a lumen 236 (FIG.14) of the cannula 216. In other embodiments, the trocar cannula 216 canhave a an instrument seal and a zero seal, separate or monolithic seals,positioned directly therein with no separate valve housing such that thetrocar cannula with a sealed instrument channel path has a relativelyshort length from a proximal end to the distal end defining a low heightprofile.

In certain embodiments, the trocar cannula assembly 210 can be sized toreceive surgical instruments such as laparoscopic surgical tools havingstandard sizes. For example, the trocar assembly 210 can be a “5 mmtrocar cannula,” sized and configured to receive surgical tools fromsized up to a 5 mm surgical tool product class. In other embodiments, atrocar assembly 210 can be an “11 mm trocar cannula” or a “12 mm trocarcannula,” sized and configured to receive surgical tools sized as largeas an 11 mm or 12 mm surgical tool product class respectively. In someembodiments, the trocar cannula assembly 210 can be included in a kitcomprising the trocar cannula assembly 210, a seal housing 212 and anobturator insertable through the seal housing 212 and the cannulaassembly 210.

With reference to FIGS. 13-14, the trocar cannula 216 can include afluid inlet port 226. The fluid inlet port 226 is adapted to receive asource of fluid such as a syringe. The fluid can comprise air, anothergas such as carbon dioxide, a gas mixture, or a liquid such as water, asaline solution, or another liquid solution. As further discussedherein, the fluid inlet port 226 is fluidly coupled to the sleeve 218such that addition of fluid to the fluid inlet port 226 inflates theballoon 220.

In some embodiments, the fluid inlet port 226 can include a one-wayvalve such as a poppet valve or check valve 228. Once fluid is added tothe fluid inlet port 226 through the check valve 228, the check valve228 maintains the fluid within the sleeve 218 and balloon 220 of thetrocar cannula assembly 210. The check valve 228 can be selectivelyopened to allow the fluid to escape or be withdrawn such as by syringewhen it is desired to deflate the balloon 220.

Trocar Cannula

With reference to FIG. 15, in some embodiments, the trocar cannula 216has a proximal end 230, a distal end 232, and a lumen 236 extending fromthe proximal end 230 to the distal end 232 along a longitudinal axis L.The lumen 236 is configured to receive a surgical instrument thereinsuch as a laparoscopic surgical tool.

With continued reference to FIG. 15, in some embodiments, the trocarcannula 216 comprises a seal housing interface 238 at the proximal end230, the fluid inlet port 226 distal the seal housing interface 238, agenerally tubular cannula body 240 extending distally from the fluidinlet port 226, an annular recess such as an annular groove 242 in thecannula body 240 adjacent the distal end 232 of the cannula 216, and adistal tip 244. The seal housing interface 238 can comprise a seal suchas an O-ring 246 (FIG. 14) to sealingly engage a seal housing.

In the illustrated embodiments, the fluid inlet port 226 comprises afluid inlet 250 and a fluid dome 252. The fluid inlet 250 is configuredto receive the source of inflation fluid and can include the check valve228 positioned therein (FIG. 14).

As illustrated, the fluid dome 252 of the fluid inlet port 226 isfluidly coupled to the fluid inlet 250. In some embodiments, the fluidinlet port 226 can have a generally smooth outer surface 254. The smoothouter surface 254 can allow adhesive to flow underneath the sleeve 218and obtain a relatively strong balloon-to-cannula bond. In someembodiments, the fluid inlet port 226 can be shaped with a curvedprofile such as a generally teardrop shape and the fluid dome 252 canhave a curved profile to reduce the likelihood of the fluid pathway forballoon inflation/deflation can become plugged. In other embodiments,the fluid inlet port 226 can have another curved profile such as agenerally cylindrical, elliptical, or oval profile. In otherembodiments, the fluid inlet port 226 can have another curvilinearprofile.

Cannula Body

With continued reference to FIG. 15, in some embodiments, the cannulabody 240 extends distally from the fluid inlet port 226 to the distalend 232 of the cannula 216. The cannula body 240 has an exterior surface260 and a first outer diameter D1. In some embodiments, the exteriorsurface 260 of the cannula body 40 can be configured to facilitateinstallation of the sleeve 218 thereon. For example, the exteriorsurface 260 of the cannula body 240 can include a relatively lightlytextured surface finish to facilitate sliding advancement of the sleeve218 over the cannula body 240.

In some embodiments, the cannula body 240 can include one or more fluidchannels 262 or grooves that extend generally longitudinally from thefluid inlet port 226 towards the distal end 232 of the cannula 216. Thefluid channel 262 can be formed in the exterior surface 260 of thecannula body 240 and extend a depth d into the cannula body 240. Asillustrated, the fluid channel 262 is fluidly coupled to the fluid inletport 226 and extends distally to a location adjacent the balloon 220 ofthe sleeve 218. (FIG. 14). The fluid channel 262 can thus work inconjunction with the balloon 220 to allow fluid passage for balloon 220inflation and deflation. Advantageously, with the fluid channel 262embedded in the cannula body 240, the sleeve sub-assembly 214 can have arelatively small outer diameter and low-profile. Desirably, with arelatively small diameter and low-profile, the cannula assembly 210 canhave a relatively low insertion force. Similarly, the balloon 220 andfluid channel 262 geometry can reduce the incidence of the balloon 220plugging the fluid flow path during deflation.

With continued reference to FIG. 15, the cannula body 240 can include anannular recess such as an annular groove 242 adjacent the distal end ofthe trocar cannula 216. In some embodiments, the annular groove 242 isformed in the cannula body 240 at an orientation generally perpendicularto the longitudinal axis L of the trocar cannula 216. In otherembodiments, other orientations of the annular groove 242 can be formed.In certain embodiments, as illustrated, the annular recess comprises anannular groove 242 having a recessed surface extending a relativelyshort length along the longitudinal axis L of the trocar cannula 216adjacent the distal end of the trocar cannula 216. In other embodiments,the annular recess or annular groove can include a recessed surfaceextending from a location adjacent the distal end proximally to alocation between the proximal end or the distal end of the trocarcannula 216 or to a location adjacent the proximal end of the trocarcannula 216.

FIG. 16 illustrates a cut away detail view of an embodiment of annulargroove 242. In some embodiments, the annular groove 242 can have aproximal edge 270, a distal edge 272, and an annular interface surface274 between the proximal edge 270 and the distal edge 272. The annularinterface surface 274 can have a second outer diameter D2 smaller thanthe first outer diameter D1 of the cannula body 240. The proximal edge270 can have a generally stepped edge extending between the first outerdiameter D1 of the cannula body 240 and the second outer diameter D2 ofthe annular interface surface 274. Desirably, the stepped edge canenhance sealing performance of the sleeve 218 to the cannula body 240 tomaintain fluid within the balloon 220 in an inflated configuration.

With continued reference to FIG. 16, in some embodiments, the distaledge 272 of the annular groove 242 can have a ramped edge. The rampededge can extend at an angle transverse to the annular interface surface274. In other embodiments, the distal edge 272 of the annular groove 242can comprise a generally stepped edge or an edge having anothergeometric profile such as a radiused curvilinear edge.

With reference to FIG. 15, in some embodiments, the distal tip 244 atthe distal end 232 of the cannula 216 has a distal edge 278 that extendsat an angle 8 relative to a plane perpendicular to the longitudinal axisL of the cannula 216. The angle θ can be between about 5 degrees andabout 45 degrees. In some embodiments, of cannula assembly 210 having a5 mm size, the distal edge 278 of the distal tip 244 can be angled atapproximately 17 degrees relative to the plane perpendicular to thelongitudinal axis L. In embodiments of cannula assembly 210 having othersizes, for example 11 mm and 12 mm cannulae, the angle can be slightlydifferent to match the correlated cannulae 216. For example, in someembodiments of 11 mm cannula assembly, the angle θ can be approximately20 degrees, and in some embodiments of 12 mm cannula assembly, the angleθ can be approximately 12 degrees. In other embodiments of cannulaassembly 210 other angles can be used.

Advantageously, the angled distal tip 244 can greatly reduce the forcerequired to insert the cannula assembly 210 through a body wall such asthe patient's abdominal wall as compared with a distal tip having astraight tip with a distal edge perpendicular to the longitudinal axisof the cannula. Balloon trocars having straight tips have primarily beenintroduced through body walls into surgical sites through relativelylarge incisions using a cut-down technique. Desirably, the angled distaltip 244 can facilitate the use of a fixation cannula in surgicalprocedures including various cannula insertion techniques with variousincision lengths. For example, a fixation trocar having an angled distaltip can be inserted with a relatively low insertion force with insertiontechniques including insertion techniques with bladed, non-bladedoptical, or insufflation obturators.

In some embodiments, the cannula body 240 can be formed of apolycarbonate material. Desirably, the hardness and relative rigidity ofthe material allows the cannula 216 to serve as a supporting tube toinstall the flexible sleeve 218 and balloon 220 and a port to insertobturators or other medical instruments. In other embodiments, thecannula body 240 can comprise other materials.

Sleeve

In certain embodiments, a sleeve extends from adjacent the proximal endof the trocar cannula to adjacent the distal end of the trocar cannula.The sleeve has a proximal end and a distal end with an inflatablesegment adjacent the distal end. The sleeve can be coupled to the trocarcannula at the proximal end of the sleeve and the distal end of thesleeve.

The sleeve can be coupled to the trocar cannula by a technique thatcreates a relatively low diametric profile at the coupling, hasdesirable sealing performance, and can be efficiently manufactured. Forexample, in some embodiments, the trocar cannula can have asubstantially smooth continuous outer surface, and the sleeve can becoupled to the smooth surface by application of an adhesive to form achemical bond. In other embodiments, the sleeve can be coupled to thetrocar cannula by heat welding or UV welding to create a fused coupledregion. In some embodiments, as further discussed with respect to FIGS.17 and 18, the sleeve can be coupled to the trocar cannula at anon-continuous region of the outer surface, such as, for example one ormore annular grooves formed therein. In some embodiments, differentcoupling techniques can be used at the proximal end of the sleeve thanare used at the distal end, while in other embodiments, substantiallysimilar coupling techniques can be used at the proximal end and thedistal end of the sleeve.

With reference to FIGS. 17-18, an embodiment of sleeve 218 for thecannula assembly 210 is illustrated. In the illustrated embodiment, thesleeve 218 comprises a proximal interface section 280 or coupler at theproximal end 281, an elongate tubular body 282 extending distally fromthe coupler, a balloon 220 positioned distal the elongate tubular body282, and an annular ring 284 distal the balloon.

In some embodiments, the sleeve 218 can be monolithically unitarilyformed, such as by stretch blow molding. Advantageously, thestretch-blow molding process allows for a high degree of control of theballoon material, thickness and shape.

The sleeve 218 can comprise a polyolefin material such as one commonlyused as heat shrink tubing. In certain embodiments, a Sumitomo A2 clearpolyolefin tubing can be used. Advantageously, a sleeve 218 comprising apolyolefin material, is latex free, non-porous, and non-fragmenting,unlike latex or silicone rubber materials. Desirably, the polyolefintubing material can be soft, flexible, and can include a high degree ofcross-linking such that it has a relatively high strength for a givenmaterial thickness compared to other tested materials. In embodiments ofcannula assembly 210 having a polyolefin sleeve 218, despite having anincredibly thin balloon section, the balloon 220 can typically beover-inflated with an average of 5 times of a designed inflationpressure without rupturing. Also, the softness and flexibility of thepolyolefin material improves the feel of the device for the user whilealso reducing the insertion force. In other embodiments the sleeve cancomprise other materials such as a silicone material, cilran,polyisoprene, a polyurethane material, a polyurethane blend, TYGON®,VITON®, SANTOPRENE®, MYLAR®, or another suitable polymeric material.

In the illustrated embodiment, the cannula assembly includes one balloon220 positioned at a distal location on the cannula 216. It iscontemplated that in various other embodiments, additional balloons canbe incorporated to account for variations in a patient's abdominal wallthickness and anatomy. Also, balloons at different locations may usedifferent material. The balloon may be distensible or non-distensible ora combination of both. The balloon 220 in one embodiment is doughnutshaped or in one aspect disc-like. The size and/or location of theballoon 220 can vary to vary the desired retention of the trocar cannula216 with the patient's body.

With continued reference to FIGS. 17 and 18, the coupler 280 is sizedand configured to engage the cannula 216. For example, in theillustrated embodiment, the coupler 280 has a curved profile in aneccentric or generally teardrop shape to match the teardrop shape of thefluid dome 252 of the cannula 216. Advantageously, this matching profilecan allow a tight fit when the sleeve 218 is installed on to the cannula216, reducing the potential for leakage therebetween.

In some embodiments, an outer surface 286 of the coupler at the proximalend 281 is textured. The rough surface facilitates the bonding ofadhesives to the sleeve 218, preventing the sleeve 218 from beingseparated from the cannula 216 when the balloon 220 is fully inflated.For example, a roughened or textured surface can create a plurality ofrelatively small channels which enhance flow of a chemical adhesivethough a wicking or capillary action process to create a strong adhesivebond between the sleeve 218 and the cannula 216. Desirably, a texturedor roughened surface at the coupler can allow the sleeve 218 to comprisea material that can be otherwise difficult to bond with adhesives.

With continued reference to FIGS. 17-18, the elongate tubular body 282or shaft of the sleeve 218 extends distally from the coupler 280. Theshaft is uniform and thin-walled, but thick enough to withstand slidingmovement of a retention disc 222 or other bolster.

FIG. 19 illustrates a distal end of the cannula assembly 210 with thesleeve 218 positioned on the cannula 216. Advantageously, a sleeve 218formed by a stretch blow molding process can allow for increased controlof the thickness t1 of the elongate tubular body 282 to minimize anouter diameter of the trocar cannula assembly 210 resulting in a smallerincision size for the patient. In some embodiments, the elongate tubularbody 282 can have a thickness t1 of approximately 0.008 inches toapproximately 0.012 inches.

With continued reference to FIG. 19, as illustrated, the sleeve 218comprises a non-distensible inflatable balloon 220 distal of theelongate tubular body 282. The balloon 220 can have a thickness t2 thatis smaller than the thickness t1 of the elongate tubular body 282.Advantageously, stretch blow molding a polyolefin material to form theballoon 220 can provide a high strength material with a relatively lowthickness. In some embodiments, the balloon can have a thickness betweenabout 0.0005 inches and 0.002 inches. In certain embodiments, theballoon can have a thickness of approximately 0.001 inch.

Advantageously, abrupt thickness transitions at the balloon/shaftinterfaces can be significantly reduced or eliminated through thestretch blow molding process. Desirably, the relatively high degree ofcontrol in the balloon thickness of the stretch blow molding process canalso contribute to a minimized outer diameter adjacent the distal end ofthe cannula assembly, resulting in a reduction in insertion force.

With reference to FIGS. 17-19, the sleeve 218 further comprises anannular ring 284 distal the balloon 220. The annular ring 284 has anouter diameter DO, an inner diameter D3 in an undisturbed state, athickness t3 between the inner diameter D3 and the outer diameter DO,and a length l2. In embodiments of trocar cannula assembly 210 having asleeve 218 that is formed in a monolithic unitary construction, theannular ring 284 can comprise a segment of material having an outerdiameter DO smaller than an outer diameter of the elongate tubular body282. In the illustrated embodiment, the thickness t3 of the annular ring284 is greater than the thickness t1 of the elongate tubular body 282.Accordingly, the annular ring 284 is relatively rigid compared with theelongate tubular body 282.

In the illustrated embodiment, the inner diameter D3 of the annular ring284 in the undisturbed state is smaller than the outer diameter D2 ofthe annular groove 242. In some embodiments, a ratio of the innerdiameter D3 of the annular ring 284 in the undisturbed state to theouter diameter D2 of the annular groove 242 and can be betweenapproximately 75:100 and approximately 85:100. Desirably, thisundersized relationship of the annular ring 284 relative to the annulargroove 242 provides a snap-ring design having an interference fit thatcan assist in attachment of the sleeve 218 to the cannula 216. Invarious embodiments having different trocar cannulae diameters,different undersized ratios can be used. For example, in an exemplaryembodiment of 5 mm trocar cannula assembly, inner diameter D3 of theannular ring 284 in the undisturbed state can be approximately 0.24inches and the outer diameter D2 of the annular groove 242 can beapproximately 0.32 inches, resulting in an undersized ratio ofapproximately 76:100. In an exemplary embodiment of 11 mm trocar cannulaassembly, inner diameter D3 of the annular ring 284 in the undisturbedstate can be approximately 0.42 inches and the outer diameter D2 of theannular groove 242 can be approximately 0.5 inches, resulting in anundersized ratio of approximately 84:100. In an exemplary embodiment of12 mm trocar cannula assembly, inner diameter D3 of the annular ring 284in the undisturbed state can be approximately 0.49 inches and the outerdiameter D2 of the annular groove 242 can be approximately 0.57 inches,resulting in an undersized ratio of approximately 85:100. In otherembodiments, it is contemplated that other undersized ratios can beused. As the sleeve 218 is installed on the cannula 216, its undersizedannular ring 284 tightly fits in the annular groove 242 of the cannula216. The interference fit of these two components maximizes a sealingeffect, preventing air from leaking between the sleeve 218 and thecannula 216.

Advantageously, the snap-ring design reinforces a distal hoop strengthof the cannula 216 after the balloon 220 is installed. In someembodiments, the annular ring 284 and the annular groove 242 are sizedand configured such that the outer diameter DO of an outer surface 288of the annular ring 284 is flush with or recessed from an outer surfaceof the distal tip 244 of the cannula. The snap fit ring design allowsfor a smooth transition from cannula distal tip 244 to balloon 220,therefore reducing the insertion force. In some embodiments, the annulargroove 242 can be positioned adjacent the distal end of the cannula body240 such that the cannula 216 can have an optimized insertion forcereduction without compromising a working distance of the cannulaassembly 210.

FIG. 20 illustrates a cut-away detail view of the distal end of thecannula assembly 210 with the sleeve 218 positioned on the cannula 216.With reference to FIGS. 19-20, in some embodiments, the outer surface288 of the annular ring 284 at the distal end 283 of the sleeve 218 istextured, providing a rough bonding surface to assist in the bonding ofadhesives to the sleeve 218 by retaining adhesive and to promote flow ofthe adhesives between the sleeve and the cannula by wicking of adhesivethrough a capillary action process. In some embodiments, a combinationof cyanoacrylate instant adhesive and UV cure adhesive can be used forthe sleeve-cannula bond coupling the annular ring 218 to the annulargroove 242. In other embodiments, other adhesives, such as only acyanoacrylate adhesive or only a UV cure adhesive, or another type ofadhesive can be used. Desirably, the adhesive can be appliedsubstantially within the annular groove 242 such that the distal end 232of the cannula 216 can have a smooth low profile transition between thesleeve 218 and the cannula 216. Advantageously, the low profiletransition between the sleeve 218 and the cannula 216 can reduce theinsertion force required to position the cannula assembly 210 in asurgical site.

In some embodiments, the low profile transition can be further enhancedby disposition of an adhesive 290 predominantly within the annulargroove 242 of the cannula body 240. The annular ring 284 of the sleeve218 and the annular groove 242 of the cannula 216 can be sized andconfigured to facilitate the disposition of the adhesive 290predominantly within the annular groove 242. For example, in someembodiments, the annular surface of the annular groove has a firstlength l1 along the longitudinal axis of the cannula, the annular ringhas a second length l2 along the longitudinal axis of the cannula, andthe second length is smaller than the first length. Thus, in someembodiments, the annular interface surface 274 of the annular groove 242can comprise an engagement segment 291 and an exposed segment 293. Theengagement segment 291 can be defined by the second length l2 andengaged by the annular ring 284. The exposed segment 293 can be definedby a difference between the first length l1 and the second length l2.The exposed segment 293 can desirably be sized to provide a sufficientsurface for disposition of a bead of adhesive to maintain the annularring 284 of the sleeve 218 with respect to the annular groove 242. Thus,in some embodiments, an adhesive 290 can be at least partially appliedto the exposed segment 293 of the annular interface surface 274 tocouple the annular ring 284 to the annular groove 242.

In some embodiments the sleeve 218 can be adhesively bonded to thecannula 216 at the proximal interface surface 280 or coupler with acombination of cyanoacrylate instant adhesive and UV cure adhesivesimilar to the adhesive bonding of the annular ring 284 to the annulargroove 242. In other embodiments, other adhesives, such as only acyanoacrylate adhesive or only a UV cure adhesive, or another type ofadhesive can be used.

Retention Disc

FIGS. 21 and 22 illustrate a retention disc 222 for positioning on thecannula assembly 210. In some embodiments, the cannula assembly 210includes a proximal fixation member such as a retention disc 222positioned proximal the balloon 220 around the elongate tubular body 282of the sleeve 218. After the trocar cannula assembly 210 is insertedthrough a body wall at a surgical site, the balloon 220 can be inflatedto maintain the position of the trocar cannula assembly 210 in thesurgical site, and the proximal fixation member or retention disc 222can prevent the trocar cannula 216 from advancing further into thesurgical site.

As illustrated in FIG. 22, the retention disc 222 can comprise agenerally circular disc with a center hole 292 defining a passage 294through the retention disc 222. The passage 294 of the center hole 292can have a ribbed profile on an inner diameter. The ribbed profile caninclude a plurality of annular grooves 296. The ribbed profile canfrictionally engage an outer surface of the elongate tubular body 282 ofthe sleeve 218 such that the retention disc 222 is manually slidablealong the sleeve 218 but tends to remain in a selected position.

In some embodiments, the retention disc 222 can be formed of anelastomeric polymer material such as a KRATON® material. A retentiondisc 222 formed of a KRATON® material can provide a desired level offrictional engagement with the outer surface of the sleeve 218 andpresent an ergonomically pleasing soft, flexible feel to a user of thetrocar cannula. Advantageously, the round corners and soft material ofthe retention disc 222 provide an atraumatic means to hold the trocar inplace. In some embodiments, the retention disc 222 can be formed by aninjection molding process. Advantageously, embodiments of a trocarcannula having a single molded retention disc 222 can have manufacturingand assembly efficiencies and facilitate ease of use relative to a clampmechanism having multiple assembled components.

In some embodiments, the trocar cannula assembly 210 can be configuredto resist movement of the retention disc 222 proximally along thecannula body 240 to prevent the trocar cannula 216 from advancingfurther into the surgical site. For example, an exterior surface 260 ofthe cannula body 240 can have a slight taper such that it has a smallerouter diameter at the distal end relative to the outer diameter at theproximal end of the cannula body. Thus, a friction force generated bythe frictional engagement between the retention disc 222 and the sleeve218 can increase as the retention disc 222 is slid proximally along thetrocar cannula 216. The retention disc 222 can be used to fixate thetrocar cannula 216 relative to a body wall. The tight fit, ribbedprofile, and tapered cannula 216 prevent the retention disc 222 fromadvancing along the cannula body 240 when an instrument is inserted intothe cannula 216.

In some embodiments, a retention disc 222 comprising an elastomericpolymer material can exhibit creep when stored under tension.Advantageously, where the exterior surface 260 of the cannula body 240includes a slight taper, before use the retention disc 222 can bepositioned adjacent the distal end having a relatively small outerdiameter when not in use to reduce the incidence of creep in theretention disc 222. During use, the retention disk 222 is advancedproximally up the shaft of the cannula 216 to an area of larger cannuladiameter, allowing placement and fixation of the disc 222. Additionally,such a tapered cannula body 240 can have further advantages inmanufacturability of the cannula body 240. For example, such a taperedprofile can facilitate release of the cannula body 240 from a mold inembodiments where the cannula body 240 is formed with an injectionmolding process.

In other embodiments, the cannula assembly 210 can comprise a bolster222′ (See, e.g., FIGS. 31-36) such as a generally cylindrical or conicalstability member with a clamp mechanism. For example, in someembodiments the cannula assembly 210 can include a stability assemblyincluding one of the various clamp mechanisms described in U.S. Pat. No.8,162,893, to Okihisa et al., entitled “TROCAR STABILITY ASSEMBLY,”which is incorporated herein by reference in its entirety.

Sleeve Protector and Balloon Folding

With reference to FIGS. 23-24, in some embodiments, a trocar assembly210 can include a sleeve protector 224 to maintain a position of theballoon 220 relative to the body 240 and to protect the balloon 220during shipping. Moreover, the required insertion force can be observedto vary proportionally with an overall outer diameter of the trocarcannula assembly 210 at the balloon 220. Thus, before use, it can bedesirable to reduce insertion force by folding the balloon 220 into aninsertion configuration having a relatively smooth transition from thedistal tip 244 of the cannula 216 to the balloon 222.

A non-elastic or non-distensible balloon 220 in a deflated or insertionconfiguration does not automatically conform to the exterior surface 260of the cannula body 240. In some embodiments, the material can have atendency to wrinkle, form folds and/or creases and may project atvarious points away from the exterior surface 260 of the cannula body240. The irregularities that the un-inflated balloon may possess, canpresent resistance during insertion of the un-inflated retention balloon220 through a body wall. Folding the balloon 220 into the insertioncondition can reduce the force required for insertion. In someembodiments, in the insertion configuration the balloon 220 is foldedalong the cannula body 240 towards the proximal end 230 of the cannula216. Folding the balloon 220 towards the proximal end 230 can result inone or more folds in the balloon 220 in the insertion configuration. Forexample, in some embodiments, the balloon 220 can be folded proximallyin a single step and in other embodiments, the balloon 220 can beinitially folded distally in a first fold and subsequently foldedproximally in a second fold. By folding the balloon 220 against thetrocar placement direction, it helps reduce the insertion force andlower the balloon diametric profile. The sleeve protector 224 canmaintain the balloon 220 in the insertion configuration until it isremoved from the trocar cannula assembly 210 for insertion to a surgicalsite. Moreover, the sleeve protector 224 can protect the balloon 220and/or distal tip 244 of the cannula assembly 210 from damage duringshipping or prior to operational use.

FIG. 23 illustrates a sleeve protector 224 comprising a hollow tubularsegment. The sleeve protector 224 can be configured to provide arelatively small area of surface contact with the balloon 220 of thesleeve 218. The sleeve protector 224 can comprise an inner surface 300having a plurality of radially inwardly projecting ribs 302 extendinggenerally longitudinally. With the sleeve protector 224 positioned onthe trocar assembly 210, the ribs 302 can contact an outer surface ofthe balloon 220 in the insertion configuration. Desirably, therelatively small amount of surface contact between the ribs 302 and theballoon 220 can reduce the incidence of wear on the balloon 220 from thesleeve protector 224. Moreover, as discussed further below, the ribs 302can be configured to reduce the insertion force of the trocar cannulaassembly 210. In the illustrated embodiments, the ribs 302 are radiused,which can facilitate installation and removal of the sleeve protector224 and can further reduce wear on the balloon 220.

In one embodiment, It can be desired that the sleeve protector 224 isconfigured to prevent proximal movement of the sleeve protector 224 pastthe balloon 220. In some embodiments, the sleeve protector 224 is shapedto have a somewhat smaller diameter at a distal end than at a proximalend to prevent the sleeve protector 224 from moving proximally and pastthe balloon 220 to maintain the sleeve protector 224 on the balloon 220.In other embodiments, the sleeve protector 224 may have detents orprojections that prevent the sleeve protector 224 from movingproximally. In some embodiments, the cannula assembly 210 can furthercomprise a spacer between the retention disk 222 or bolster 222′ and thesleeve protector 224 to prevent the sleeve protector 224 from movingproximally past the balloon 220. The retention disk 222 or bolster 222′in one embodiment is positioned near the balloon 220 or the sleeveprotector 224 is sufficiently long to contact the retention disk 222 orbolster 222′ to prevent the sleeve protector 224 from moving proximallypast the balloon 220. Preventing the sleeve protector 224 from movingproximally past the balloon 220 prevents the sleeve protector 224 fromlosing contact with the balloon 220 losing pressure and protection ofthe balloon 220 and tip 244.

In one embodiment, the sleeve protector 224 is incorporated into orattached to the retention disk 222 or bolster 222′. As such, the sleeveprotector 224 attached to the bolster 222′ can maintain the balloon 220in the folded position. During operation, the retention disk 222 orbolster 222′ is moved proximally and along with it the sleeve protector224 to expose the balloon 220. In one embodiment, the sleeve protector224 is removably attached to the retention disk 222 or bolster 222′ andthus moved distally to expose the balloon 220 and remove the sleeveprotector 224 from the bolster 222′.

Method of Manufacture

FIGS. 25-29 illustrate various embodiments of methods for manufacture oftrocars described herein. Embodiments of cannula assembly 210 discussedherein can include a preformed sleeve 218. In some embodiments, thecannula 216 can be formed from a suitable material, such as apolycarbonate material, with an injection molding process. The sleeve218 can be formed apart from the cannula 216 with a stretch blow-moldprocess and subsequently assembled to the cannula 216.

With reference to FIG. 25, a method of making a cannula assembly 210 isillustrated. In some embodiments, a roll of polyolefin heat-shrinktubing is cut into sections or blanks then heated to shrink the tubingdown. Each section or blank of tubing is then heated, stretched andinflated into a conditioning mold having a desired geometry tostretch-blow-mold 402 and pre-form the sleeve. The preformed sleeve 218can include a proximal end 281, a distal end 283, a proximal interfacesection 280, an elongate tubular body 282, a balloon 220 distal thetubular body 282, and an annular ring 284 distal the balloon 220 asdiscussed herein with respect to various embodiments of cannula assembly210.

With reference to FIG. 26, In some embodiments, the sleeve 218 can bestretch blow molded to a slightly oversized profile relative to theexterior surface 260 of the cannula body 240 to facilitate installationof the sleeve 218 on the cannula 216. Once the slightly oversizedpreformed sleeve 218 is installed on the cannula 216, the sleeve 218 canbe heated 416 to shrink onto the exterior surface 260 of the cannulabody 240. For example, the elongate tubular body 282 of the sleeve canbe formed line-to-line for installation and then heated slightly toshrink down onto the exterior surface 260 of the cannula body 240.

With reference to FIG. 27, in some embodiments, once the stretch blowmolding 402 has been completed, the pre-formed sleeve 218 can be trimmedon the proximal end 281 and a rough cut is made at the distal end 283 toform or create 404 a distal installation cup 285, as shown in FIGS. 17and 18. An inner surface 287 of the sleeve 218 can generally match anexterior surface 260 of the cannula body 240, making it easy to slideover the cannula 216 and install the balloon 220. After installation ofthe balloon 220 onto the cannula 216, the distal installation cup 285 istrimmed 414 and removed. Desirably, the distal installation cup 285 canprovide a surface for distal balloon installation equipment tomanipulate the sleeve 218 and advance the sleeve 218 relative to thecannula 216. Advantageously, this distal installation cup 285 provides asacrificial portion of the distal end 283 that allows installation whileprotecting the snap-ring features of the annular ring 284 from damage.

With reference to FIG. 28, in some embodiments, by forming the balloon220 of the sleeve 218 separately from the cannula 216, the balloon 220can be molded in one shape or width, but installed and attached in adifferent shape and width. For example, in some embodiments, thepre-formed balloon 220 is blow-molded or formed 406 with a circular discshaped balloon, as shown in FIGS. 17-18. After installing the sleeve 218on to the cannula 216, the distal end 283 of the sleeve 218 is advanced408 towards the proximal end 281 of the sleeve 218 to reconfigure theballoon 220 of the sleeve 218 into a generally toroidal or donut shapedballoon as shown in FIG. 19. In other embodiments, the preformed sleeve218 can include a balloon 220 having other geometries, such as agenerally frusto-conical profile or another rounded profile.Advantageously, this control in balloon shape can maximize the totalworking distance of the device. Furthermore, the round balloon shape andsoft material provides an atraumatic means to hold the trocar assembly210 in place.

The preformed sleeve 218 can be advanced 410 over the cannula 216. Thesleeve 218 can be advanced until the proximal interface section 280 ofthe sleeve 218 is positioned about a fluid inlet port 226 of the cannula216 and the annular ring 284 of the sleeve 218 is positioned 412 in theannular groove 242.

Accordingly, the stretch blow molding process for the sleeve 218 resultsin the potential for faster processing, more consistent manufacturingand increased ability to design, shape and form the sleeve 218 ascompared with a process including forming a balloon 220 on the cannula216. Thus, the stretch blow molding process can be used to preform asleeve 218 having relatively thin-walled sections as discussed abovewith respect to various embodiments of cannula assembly 210. Desirably,the use of the pre-formed sleeve 218 simplifies the manufacturingprocess of the sleeve sub assembly 214. Stretch blow molding the sleeve218 can allow for a high degree of control of the sleeve 218 profile.Thus the pre-formed sleeve 218 can have a profile, such as with aproximal interface section 280 and an annular ring 284 with aninterference fit relative to an annular groove 242 of the cannula 216 tofacilitate sealing engagement to the cannula 216 by adhesive bondingwithout distal and proximal thread windings. Advantageously, the use ofa pre-formed sleeve 218 can therefore increase manufacturingefficiencies while reducing insertion force requirements for theresulting cannula assembly 210.

With reference to FIG. 29, once the preformed sleeve 218 has beenadvanced over the cannula 216 and the annular ring 284 of the sleeve 218is positioned within the annular groove 242 of the cannula 216, thesleeve 218 can be coupled to the cannula 216. For example, in someembodiments, the proximal end 281 of the sleeve 218 and the distal end283 of the sleeve 218 are each bonded 418 to the cannula 216. In someembodiments, the proximal interface section 280 of the sleeve 218 isadhered 420 to a location adjacent the proximal end 230 of the cannula216 and the annular ring 284 is adhered 422 to the annular groove 242.For example, one or more of a cyanoacrylate adhesive and a UV curebonding adhesive can be used to couple the sleeve 218 to the cannula216.

The retention disc 222 can be positioned 424 proximally of the balloon220 around an outer surface of the sleeve 218. When installing theretention disc 222 on to the sleeve sub assembly 214, a fixture can beused to slightly expand the disc 222 to install over the balloon 220 andto avoid any possible balloon 220 damage.

The balloon 220 can be folded 426 along the elongate tubular body 282 ofthe sleeve 218 towards the proximal end 230 of the cannula 216 into aninsertion configuration. The sleeve protector 224 can then be positioned428 over the balloon 220 to keep the balloon 220 folded until use and toretain a smooth transition from cannula distal tip 244 to balloon 220.

In some embodiments, at final sleeve sub assembly 214 configuration(FIG. 13), the retention disc 222 is placed relatively close to thedistal end 232 of the cannula 216 with the sleeve protector 224 flushedagainst it. The retention disc 222 acts as an anchor and prevents thesleeve protector 224 from sliding proximally past the balloon 220 priorto use. Similarly, with a position adjacent the distal end 232 of thecannula 216, the retention disc 222 can be placed at a relatively smalldiameter of the cannula body 240 to avoid stretching the inner diameterprior to use.

With reference to FIGS. 31-39, in some embodiments, the relatively lowdiametric profile of the folded balloon 220 can be enhanced byevacuating air from the balloon 220 during folding and sterilizing theballoon 220 after positioning the sleeve protector 224. In certainembodiments, a balloon 220 attached to a cannula 216 of a trocar cannulaassembly 210 is connected to a syringe, vacuum or the like and airwithin the balloon 220 is removed. During or subsequent to the removalor evacuation of the air, the deflated balloon 220 is folded backtowards the proximal end 230 of the cannula 216. The folding and/or theremoval or lack of air in the balloon 220 is maintained. Sterilizationof the balloon 220 and/or trocar cannula assembly 210 may occur. Priorto operational use or insertion of the balloon 220 and/or cannula 216into a body cavity, the balloon 220 is allowed to unfold and airintroduced into the balloon 220. In one embodiment, maintenance of thefold is removed and/or absence of or prevention of the removal of air isdiscontinued.

In one embodiment, as a partially assembled cannula assembly 210illustrated in FIG. 30 and illustrated schematically in FIG. 31, thetrocar cannula assembly 210 initially is inflated or partially filledwith air. This inflation can occur as the balloon 220 is attached to thecannula 216. In one embodiment, the balloon 220 is formed on a stretchblow molded sleeve 218 and thus in a neutral or initial state is in anextended or inflated condition. As such, as the sleeve 218 is attachedto the cannula 216, air is trapped or caught within the balloon 220.Using a syringe fluidly coupled to the check valve 228 of the cannula216, air can be extracted from the balloon 220 via the one or more fluidchannels 262 of the cannula 216 connected to the check valve 228 and theballoon 220, as illustrated schematically in FIG. 32.

Various balloon 220 folding techniques can be used to provide arelatively low diametric profile to reduce insertion force for thetrocar cannula assembly. For example, in some embodiments, the balloon220 can be folded proximally upon itself in a single folding step. Usinga trocar tip sleeve protector 224, the balloon 220 can be pushed againstor towards a retention disk 222 or bolster 222′ causing the balloon 220to fold upon itself in a proximal direction. In other embodiments, asdescribed further below, the balloon 220 can be folded in a two-stepprocess with an initial distal fold followed by a proximal fold. Theballoon folding technique to be incorporated in a method of manufacturefor a trocar cannula assembly can be selected to provide a desiredinsertion force and ease of manufacturability.

In some embodiments, subsequent to or during the extraction of air, theretention disk 222 or bolster 222′ of the trocar without a sleeve orcone (e.g., the bolster base) can be slid or pushed against a proximalend of the balloon 220 to push or apply a force distally away from theproximal end 230 of the trocar cannula 216. The distal end 306 of thebolster can be positioned adjacent the proximal end 308 of the balloon220, as illustrated schematically in FIG. 33. Using a trocar tip sleeveprotector 224, the balloon 220 is pushed against or towards theretention disk 222 or bolster 222′ causing the balloon 220 to fold uponitself in a proximal direction. A compressive force of the trocar tipsleeve protector 224 against the balloon 220 continues as the trocar tipsleeve protector 224 slides over the balloon 220. This sliding movementfully compresses the balloon 220 into a preferred, compressed condition,as illustrated schematically in FIGS. 33 and 34. The sleeve protector224 can be advanced using a linear motion or a slight twisting motion toprovide a relatively low balloon insertion profile. The retention disk222 or bolster can be moved proximally when the sleeve protector 224 isin place covering the entire folded balloon 222. Placement of the tipsleeve protector 224 over the balloon 220 and in particular over thefold in the balloon 220 maintains the fold in the balloon 220 and/or theevacuation of air from the balloon 220. In one embodiment, a removablebase support is removably attached to the cannula 216 and used as asupport to push the proximal end of the balloon 220.

As illustrated schematically in FIG. 35, subjecting or applyingsterilization 310 to the balloon 220, e.g., applying gamma sterilizationto the balloon 220 further maintains the balloon 220 folded against thecannula 216 and further reduces the outer profile of the balloon 220 tobe flushed or flattened against or towards the outer surface of thecannula 216. The resulting inflation configuration of the balloon 220 isillustrated schematically in FIG. 36.

The sterilization 310 process in certain embodiments may includeelectron-beam, gamma radiation or heat. The irradiation provides a“setting” of the folded material to a predetermined condition, size andshape. The material of the compressed balloon 220 may be partiallycross-linked during this process. In the instance where heat may beapplied, a heat-shrinkable material may be used for the sleeve 218thereby compressing the balloon 220 without the friction associated withsliding a snug fitting sleeve protector 224 over the un-inflatedballoon. The irradiation process 220, in one embodiment, may involve asterilization process in which the assembled trocar cannula 216 andsleeve 218 with balloon 220 are sterilized for surgical use.

With reference to FIG. 37, the balloon 220 in one embodiment can bepre-creased 304 or scored or otherwise preconditioned to facilitatefolding (and/or the direction of the fold) of the balloon 220 towardsthe proximal end 230 of the balloon trocar cannula 216. The balloon 220in one embodiment is dimensioned, shaped or made of different materialsto facilitate folding of the balloon. In one embodiment, attachment ofthe balloon 220 to the cannula 216 is also positioned and specificallyplaced to facilitate folding of the balloon 220. For example, in oneinstance, a proximal end of the balloon 220 can be advanced towards adistal end of the balloon during positioning of the sleeve 218 on thecannula 216 to incline or bias a mid-point or center of the balloon 220towards the proximal end of the balloon 220. As such, the balloon 220tends to fold towards the proximal end of the balloon and the trocar andaway from the distal end. Additionally, in some embodiments, differentportions of the balloon 220 may be weakened or reinforced relative toother portions of the balloon 220 to bias or otherwise cause the balloon220 to tend to fold proximally versus distally. In one embodiment,different materials and/or layers of material are used in the balloonsuch that a proximal portion of the balloon 220 is weaker than thedistal portion of the balloon 220. In other embodiments, a supportstructure such as internal balloons, membranes or scaffoldings withinthe balloon 220 causes the balloon 220 to tend to fold proximally.

In one embodiment, ramp-like folds on the proximal portion of theballoon 220 can also reduce the insertion force of the trocar cannulaassembly 210 by slightly angling the balloon 220 to provide a taper-likeform. In some embodiments, advancement of the sleeve protector 224 withradially inwardly projecting ribs 302 over the balloon 220 can formramp-like folds on the balloon 220. In one embodiment, sterilization,such as gamma sterilization, applied to the balloon 220 causes the foldsof the balloon 220 to have pronounced ramp-like folds. However, uponinflation of the balloon 220, ramp-like folds unfold or smooth out suchthat the outer surface of the balloon 220 is smooth or free ofprojections or protrusions such that the inflated balloon 220 provides aflush arrangement of the proximal portion of the balloon 220 against theinterior of the body wall to enhance the seal against the body wall.

In one embodiment, a trocar cannula assembly 210 is provided having amechanically folded inflatable non-distensible member or balloon 220sized and configured to exhibit a first, insertion profile, and wheninflated exhibiting a second, retention profile. The first profile isprovided by mechanically compressing the balloon 220 upon a tubularstructure and supplying sterilization to set the balloon material in alow profile condition. In one embodiment, a method for folding andholding an un-inflated non-elastic retention balloon 220 in alow-profile condition is provided. The method comprises attaching theballoon 220 to an access channel or cannula 216; folding the un-inflatedballoon 220 proximally; sliding a retention member such as retentiondisk 222 or bolster to occupy the folded-over, proximal portion of theun-inflated balloon 220; sliding a sleeve protector 224 over the folded,un-inflated balloon 220; sliding the retention disk or bolsterproximally to allow the folded balloon 220 to conform to the surface ofthe cannula 216; and irradiating the assembly in a process ofsterilization. In another embodiment, a method for folding and holdingan un-inflated non-elastic retention balloon 220 in a low-profilecondition is provided. The method comprises attaching said balloon 220to an access channel or cannula 216; folding said un-inflated balloon220 proximally; sliding a retention disk 222 or bolster 222′ to occupythe folded-over, proximal portion of the un-inflated balloon 220;sliding a sleeve protector 224 over the folded, un-inflated balloon;sliding the retention disk 222 or bolster proximally to allow the foldedballoon 220 to conform to the surface of the cannula 216; andsterilizing the assembly.

In one embodiment, the taper like form of the folded balloon 220,flattened folded balloon 220, the lack of air and/or prevention of airto be reintroduced into the balloon assist in reducing insertion forceof the trocar cannula assembly 210. For example, in various testing, theaverage insertion force for a 12 mm trocar cannula assembly 210 having aballoon 220 folded in accordance with the methods discussed herein inpounds was 10.2, with a 6.1 minimum, 14.9 maximum and 2.3 standard ofdeviation. In comparison, a reference 12 mm trocar cannula assembly witha non-folded balloon had an average insertion force in pounds of 14.9,with an 8.9 minimum, 25.5 maximum and a 4.0 standard of deviation. Itshould be appreciated that the insertion force is also dependent on themedium through which the trocar cannula assembly is inserted.Accordingly, for a thicker, stronger or more puncture resistant medium,the insertion force can be higher. As such, in various testing with amore resistant medium, the average insertion force for a folded 12 mmtrocar cannula assembly in pounds was 15.8, with a 12.6 minimum, 23maximum and 2.2 standard of deviation versus a non-folded balloon trocarcannula assembly with an average insertion force of 21.3, with a 14.7minimum, 28 maximum and a 2.7 standard of deviation. It should howeverbe appreciated that the insertion force for the folded balloon trocar inaccordance with various embodiments has a lower insertion force than anon-folded or other similar balloon trocar.

In one embodiment, the taper like form of the flattened folded balloon220 and the lack of air and/or prevention of air to be reintroduced intothe balloon 220 assist in conditioning an insertion force profile of thetrocar cannula assembly 210 to facilitate insertion. In various testing,an insertion force profile for a 12 mm trocar cannula assembly with anon-folded balloon typically includes two regions of relatively highinsertion force. FIG. 38 illustrates a graph of insertion force inpounds versus a number of elapsed time samples for an exemplary 12 mmnon-folded balloon trocar as tested. In the tested exemplary trocarcannula assembly with a non-folded balloon, each time sample correspondsto a one-second measurement interval. The test was conducted beginningat time sample zero with the trocar cannula assembly an arbitrarydistance from a tissue sample and ending at an elapsed number of timesamples with the balloon 220 of the trocar cannula assembly 210 insertedthrough the tissue sample. Thus, in the illustrated exemplary data, morethan approximately 30 time samples elapse with substantially no measuredinsertion force before the balloon trocar begins to traverse the tissuesample. Once the trocar cannula assembly begins to traverse the tissuesample, insertion force ramps up to an initial peak of approximately 12pounds, falls to a reduced level of approximately 6 pounds, then rampsup to a second peak of approximately 25 pounds before the balloon isinserted. Thus, when a non-folded balloon trocar is inserted, the userwould feel two distinct regions of resistance or “bumps” upon insertion.

With reference to FIG. 39, in comparison, a trocar cannula assembly 210having a balloon 220 folded proximally in accordance with methodsdiscussed herein can have a smoothed insertion profile with a relativelylower average insertion force, as described above, and a single regionof relatively high insertion force. FIG. 39 illustrates a graph ofinsertion force in pounds versus a number of elapsed time samples for anexemplary trocar cannula assembly 210 with a folded balloon 220 astested. In the tested exemplary trocar cannula assembly 210 with foldedballoon 220, each time sample corresponds to a one-second measurementinterval. The test was conducted beginning at time sample zero with thetrocar cannula assembly an arbitrary distance from a tissue sample andending at an elapsed number of time samples with the balloon 220 of thetrocar cannula assembly 210 inserted through the tissue sample. Thus, inthe illustrated exemplary data, approximately 4 time samples elapse withsubstantially no measured insertion force before the trocar cannulaassembly 210 begins to insert into the tissue sample. Once the trocarcannula assembly 210 with the flattened folded balloon 220 begins totraverse the tissue sample, insertion force ramps up to a single peak ofapproximately 13 pounds, then falls off as the balloon 220 is insertedthrough the tissue sample. Accordingly, the flattened folded balloon 220can advantageously be easier to insert than a non-folded or othersimilar trocar cannula assembly.

Vacuum, syringes or other air evacuation devices can be used to removethe fluid from the balloon. In one embodiment, a cap can cover thecheck-valve 228 of the trocar cannula assembly 210 to facilitatemaintenance of the evacuation of fluid from the balloon 220 and toprevent seeping of ambient air into the balloon 220. Compression orrestriction of the balloon 220 by the sleeve protector 224 facilitatesmaintenance of the evacuation of air and to prevent seeping of ambientair into the balloon 220. As a balloon trocar cannula assembly 210 maybe turned and torqued against the body cavity or incision during use, aballoon 220 may rupture. The folding of the balloon 220 does notincrease the likelihood of balloon 220 rupture and prevents potentialdamage to the balloon 220 during insertion. In one embodiment, furtherapplication of the syringe or other air evacuation devices to remove airfrom the balloon are applied while the sleeve protector 224 is placed orremains on the balloon 220, during and/or after sterilization and/orprior to removal of the sleeve protector 224.

Although this application discloses certain preferred embodiments andexamples, it will be understood by those skilled in the art that thepresent inventions extend beyond the specifically disclosed embodimentsto other alternative embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Further, the variousfeatures of these inventions can be used alone, or in combination withother features of these inventions other than as expressly describedabove. Thus, it is intended that the scope of the present inventionsherein disclosed should not be limited by the particular disclosedembodiments described above, but should be determined only by a fairreading of the claims that follow.

What is claimed is:
 1. A cannula assembly comprising: a cannula having aproximal end, a distal end opposite the proximal end, and a lumenextending from the proximal end to the distal end along a longitudinalaxis, the lumen configured to receive a surgical instrument therein, thecannula comprising: a generally tubular cannula body extending fromadjacent the proximal end to the distal end of the cannula, the cannulabody having an exterior surface and a first outer diameter; an annulargroove formed in the exterior surface of the cannula body adjacent thedistal end of the cannula, the annular groove transverse to thelongitudinal axis, the annular groove having a second outer diametersmaller than the first outer diameter of the cannula body; and a sleevehaving a proximal end and a distal end, the sleeve disposed around thecannula from adjacent the proximal end to the annular groove, the sleeveformed in a monolithic, unitary construction comprising: a coupler atthe proximal end sized and configured to engage the cannula; an elongatetubular body extending distally from the coupler, the elongate tubularbody having a first thickness; a balloon positioned distal the elongatetubular body, the balloon having a second thickness smaller than thefirst thickness; and an annular ring distal the balloon, the annularring positioned in the annular groove of the cannula, the annular ringhaving a third thickness and a third inner diameter in an undisturbedstate, the third thickness larger than the first thickness of theelongate tubular body, the third inner diameter of the annular ring inan undisturbed state smaller than the second outer diameter of theannular groove to define an interference fit between the sleeve and thecannula.
 2. The cannula assembly of claim 1, wherein the first thicknessof the elongate tubular body is between approximately 0.008 inches and0.012 inches.
 3. The cannula assembly of claim 1, wherein the secondthickness of the balloon is between approximately 0.0005 inches and0.002 inches.
 4. The cannula assembly of claim 1, wherein the coupler ofthe sleeve is adhesively bonded to the cannula and the annular ring ofthe sleeve is adhesively bonded to the annular groove.
 5. The cannulaassembly of claim 4, further comprising at least one of a cyanoacrylateadhesive and an ultraviolet curing bonding adhesive adhesively bondingthe coupler to the cannula and the annular ring to the annular groove.6. The cannula assembly of claim 1, wherein the balloon has an inflatedconfiguration with a generally toroidal shape.
 7. The cannula assemblyof claim 1, wherein the distal end of the sleeve is flush with theexterior surface of the cannula body.
 8. The cannula assembly of claim1, wherein the balloon has an insertion configuration in which theballoon comprises a first distal fold and a second proximal fold.
 9. Amethod of making a cannula assembly having an inflatable ballooncomprising: stretch blow molding a blank to preform a sleeve having aproximal end and a distal end, the sleeve comprising an elongate tubularbody, a balloon distal the tubular body, and an annular ring distal theballoon; advancing the preformed sleeve over a cannula having a proximalend and a distal end, the cannula comprising an elongate cannula bodywith an annular groove formed in the cannula body at the distal end ofthe cannula; positioning the annular ring in the annular groove; andbonding the sleeve to the cannula.
 10. The method of claim 9, whereinstretch blow molding comprises forming the balloon of the sleeve to agenerally circular disk-shaped profile.
 11. The method of claim 10,wherein positioning the annular ring in the annular groove comprisesadvancing the distal end of the sleeve towards the proximal end of thesleeve such that the circular disk-shaped profile of the balloon isreconfigured into a generally toroidal profile.
 12. The method of claim9, further comprising heating the elongate tubular body after advancingthe sleeve over the cannula to shrink the elongate tubular body onto thecannula body.
 13. The method of claim 9, wherein bonding the sleeve tothe cannula comprises adhering the proximal end of the sleeve to thecannula adjacent the proximal end of the cannula and adhering theannular ring to the annular groove.
 14. The method of claim 9, whereinstretch blow molding comprises forming a sleeve further comprising adistal installation cup distal the annular ring, and wherein the methodfurther comprises trimming the distal installation cup from the sleeveafter positioning the annular ring in the annular groove.
 15. The methodof claim 9, further comprising positioning a retention disk over theelongate tubular body of the sleeve.
 16. The method of claim 9, furthercomprising folding the balloon proximally along the elongate tubularbody of the sleeve after bonding the sleeve to the cannula.
 17. Themethod of claim 16, further comprising positioning a sleeve protectorover the balloon after folding the balloon proximally along the elongatetubular body.